Those days that just start badly and keep getting worse—where everything seems engineered to trip you up—those days, sometimes the only shot we have at breaking free of that mood is to find something really, truly funny. There's something about laughter that forces you to take a step back from head-down, eyes-front survival mode in a way nothing else does. And there's science to back it up.

Laughter signals to our brains that we're in a safe situation, which means we dial back our stress responses. The link between relaxation and laughter is so strong that even anticipating a good laugh can reduce those stress hormones. And laughing has even been shown to give us some of the focus-boosting gamma wave responses that we get from meditation. (And that's barely the tip of the iceberg.)

Check out the full enchilada—er, infographic—from Happify on the health and happiness benefits of laughter below. And then check out some of 2015's funniest videos in this YouTube compilation for a head-start on your next chuckle.